Effect of B-vitamins supplementation on cognitive decline in patients with Alzheimer's disease. A systematic review and meta-analysis

Abstract

Introduction: Cognitive decline is a marker for the onset and progression of Alzheimer's disease (AD). Currently, modification of risk factors, such as nutrition, are promising for the treatment of AD. The objective was to identify the effect of B-vitamin supplementation on cognitive decline in patients with mild cognitive impairment and AD. Methodology: Systematic review and meta-analysis of the literature in five search engines (PROSPERO CRD42021247743). Controlled experiments were included, in adults aged 60 years or older, with measurement of cognitive status (ADAS-Cog, Clinical dementia rating-CDR and/ or Mini Mental State Examination-MMSE) and use of B-complex vitamin supplements individually or combined with other vitamins or drugs. Quality assessment was done with the RoB-2 tool. Independently, three investigators made the selection, extraction, and evaluation of the data. The meta-analyses used mean difference and random effect model. Results: The search found 247 references and 12 references were included for the metaanalysis. The publication bias was not found. The quality of the studies was adequate. B-vitamin supplementation had no effect on cognitive decline by ADAS-Cog (MD: 0.01; CI95%: -0.7 to 0.72), CDR (MD: -0.06; CI95% -0.48 to 0.36), and MMSE (MD: 0.3; CI95%: -0.01 to 0.61). Conclusions: Cognitive decline was invariant following B-vitamin supplementation in adults with cognitive impairment or Alzheimer's disease. Future research should focus on multi-intervention strategies.